Device for tightening and loosening current supply plates on electrodes in electric furnaces



Jan. 24, 1961 w. DAMGEN ETA]. 2,969,410

DEVICE FOR TIGHTENING AND LOOSENING CURRENT SUPPLY PLATES ON ELECTRODES IN ELECTRIC FURNACES Filed March 17, 1959 2 Sheets-Sheet 1 FIG. I

IN v/s/v r035.- WILHELM DAMGEN, KURT ZA am a a0 TTFEIED KREMER THE/R ATTORNE vs Jan. 24, 1961 w. DAMGEN ETAI. 2,969,410

DEVICE FOR TIGHTENING AND LOOSENING CURRENT SUPPLY PLATES 0N ELECTRODES IN ELECTRIC FURNACES Filed March 17, 1959 2 Sheets-Sheet 2 //v vz/vroggs: W/LHfLM 0A MGE/V. KURT ZA GER g1 GOTTFRIED KREMER BMW/6% THE IR ATTORNEYS United States Patent DEVICE FOR TIGHTENING AND LOOSENING CURRENT SUPPLY PLATES ON ELECTRODES IN ELECTRIC FURNACES Wilhelm Damgen, Hurth, near Koln, Kurt Zager, Koln,

and Gottfried Kremer, Grevenbroich, Germany, assignors to Knapsack-Griesheim Aktiengesellschaft, Knapsack, near Koln, Germany, a corporation of Germany Filed Mar. 17, 1959, Ser. No. 799,957

Claims priority, application Germany Mar. 22, 1958 6 Claims. (Cl. 13-16) The present invention relates to a device for tightening and loosening current supply plates on electrodes in electric furnaces, and more particularly on prebaked and unmachined electrodes.

Devices are known for tightening and loosening current supply plates on electrodes in electric furnaces which are suitable for self-baking electrodes surrounded with a metal sheet shell and also for pre-baked and machined electrodes.

The reason for the different design of devices serving the same purpose resides in the fact that self-baking electrodes surrounded with shells as well as pre-burnt, machined electrodes represent dimensionallystable and good current conducting structures even after the attachment of new sections. On the other hand, pre-baked, unmachined electrodes show deviations from the actual values of the diameter, the cross-sectional shape and the eccentricity of the nipple joints between the individual sections, which necessitate special devices for tightening and loosening the current supply plates.

The devices according to the invention include two systems of current supply plates which are mechanically separated, electrically interconnected, suspended from a mutual supporting ring and arranged at a determined distance from one another. Each system is provided with a pressure ring concentrically encompassing the electrode and equipped with separate means for tightening and loosening said current supply plates.

In the device intended for closed furnaces having an electrode support projecting into the furnace, a tandem arrangement of two systems of pressure cylinders is provided for with concentric arrangement of operating rods, starting from said pressure cylinders, for the two systems of current supply plates linked by means of'bell cranks with the two pressure rings.

A pressure medium acts upon one side of the pressure pistons disposed in the pressure cylinders while pressure springs are arranged on the respective opposite side of the pressure pistons.

Both systems of current supply plates are moved against the electrode by means of pneumatic or hydraulic pressure and withdrawn by the force of springs. If necessary, it is also possible to operate vice versa.

In the device according to the invention for open furnaces, the individual pressure cylinders are arranged radially at the pressure rings with respect to the electrode. The two pressure rings are fixed to the mutual supporting ring by suspension from the conduits for the cooling medium.

Also in the device intended for open furnaces, the pressure medium acts upon one side of the pressure piston while pressure springs are arranged at the respective opposite side of the pressure pistons.

In the embodiment for open furnaces, the lower system of current supply plates is moved against the electrode by spring pressure while the upper system of current Patented Jan. 24, 1961 supply plates is forced into contact by pneumatic or hydraulic pressure. It may likewise be advisable, however, to operate vice versa.

The accompanying drawings diagrammatically represent two embodiments of the device according to the invention.

Figure 1 shows a device installed in a support projecting into a closed furnace and Figure 2 illustrates a device suitable for open furnaces.

In Figure 1, the numeral 1 represents the lower part of the upper section of a pre-baked, unmachined electrode and the numeral 2 is the upper part of the lower section of a similar electrode. Both sections are interconnected mechanically and electrically in known manner by a nipple bolting 3. A special device for holding and moving forward electrodes (not shown) bears the weight of the whole electrode and transfers said weight, for example, to parts of the construction.

The electrode is loosely surrounded with a concentric support projecting into the furnace and suspended from a yoke of the main lifting and supporting means. Said support essentially consists, seen from below, of watercooled protective shell 4, the upper intermediate ring 5 and the supporting ring 6 which are bolted together.

Pendants 9 are flexibly and adjustably fixed by means of turnbuckles 8 to eyebolt sleeves 7 connected with supporting ring 6. The lower ends of pendants 9 which have likewise the form of eyebolts are flexibly connected with the upper solid journal bearings 10 of the upper system of current supply plates 11. Further 1 pendants 13 provided with turnbuckles 14 are pivotally connected with solid journal bearings 12 at the lower end of the upper system of current supply plates 11. The lower system of current supply plates 16 is flexibly suspended by way of solid journal bearings 15 from pendants 13.

.Each of the current supply plates 11 and 16 is provided at the outside with solid journal bearings 17 or 18 respectively. Solid journal bearing 17 is linked with lever 19 flexibly connected at the other end with lever 20, and solid journal bearing 18 is linked with lever 21 flexibly connected at the other end with lever 22.

The free ends of levers 2t) and 22 rest flexibly in pressure rings 23 or 24.

Pressure rings 23 and 24 which practically are only subjected to tensile stress encompass concentrically electrode 1. Pressure ring 23 is suspended from upper intermediate ring 5 by means of suspension 25 and supports, on its part, by means of attached lower suspension 26 the lower pressure ring 24-.

The angles enclosed by levers 19 and 21) or 21 and 22 are smaller than C. When these enclosed angles are enlarged the linear distance of the terminal points oflevers 19 and 20 or 21 and 22 is enlarged, too. This means that the current supply plates 11 or 16 are moved against electrode 1, since the terminal point of lever 20 or 22 is stationary. On the other hand the current supply plates 11 or 16 are withdrawn from the electrode 1 when the angle is reduced.

The change of the angles is controlled by poweroperated driving rods which can be moved parallel to the axis of the electrode. Driving rod 27, which is flexibly connected with piston rod 29 by link 28, acts on the connection point of levers 21 and 22.

Piston rod 29 carries at its upper end piston 30 which can move up and down in pressure cylinder 31 closed at the upper end. When pressure medium is conducted through short pipe 32 on the upper side of pressure piston 30, said piston moves downwards and driving rod 27 linked with piston rod 29 likewise moves downwards and tries to bring the two levers 21 and 22in a straight-- position thus pressing the current supply plates 16 against the electrode 1 as represented in Figure 1.

It is necessary to arrange link 28 between connecting rod 27 and piston rod 29 since piston rod 29 can only accomplish a rectilinear motion whereas the motion of the lower end of connecting rod 27 likewise comprises a motion component in radial direction, referred to the axis of the electrode.

When the pressure of the medium on the upper side of piston 30 subsides the pressure spring 33 installed under the piston and supported by the intermediate bottom 34 presses the piston 31 again in its upper end position whereupon the current supply plates 16 are withdrawn from the electrode 2.

The driving rods for the upper system of current supply plates 11 are formed in analogous manner.

In view of the narrow space within the support projecting into the furnace piston rod 37 and connecting rod 35 linked therewith by joint 36, which connecting rod acts, on its part, on the connection point of levers 19 and 20, consist in this case of tubes through which piston rod 29 is guided.

Tube 37 serving as piston rod projects through stuffing box 38 into pressure cylinder 3? closed at the bottom and carries at the upper end pressure piston 40. When pressure medium is admitted through short pipe 41 under pressure piston 41) the latter moves upward taking along piston rod 37 and driving rod 35 linked therewith and forces via levers 19 and 20 the current supply plates 11 into contact with the electrode 1. When the pressure of the medium subsides under the pressure piston pressure spring 42 supported by intermediate bottom 34 presses the pressure piston 41) again in its lower end position and the current supply plates 11 are withdrawn from the electrode 1.

The straight guidance of the piston rod 29 is warranted by the guide elements 43 and 44 installed in tube 37 while the tube 37 itself is guided by pressure piston 40 and rod bearing 45 resting in the lower part of supporting ring 6.

The two pressure cylinders 31 and 39 are disposed in tandem arrangement vertically one above the other on supporting ring 6, both being provided with intermediate bottom 34.

In the arrangement described above and represented in Figure 1 the current supply plates 11 and/or 16 are pressed on electrodes 1 and/or 2 as long as the pressure medium acts upon the corresponding and individually controllable pistons 36 and/ or 40. When said pressure is released the pressure springs 33 and/ or 42 cause the loosening of the current supply plates.

The embodiment of the device according to the invention represented in Figure 2 is intended for open furnaces in which the space saving in the horizontal line is not so important as in closed furnaces having an electrode support projecting into the furnace.

In Figure 2, the numerals 1 and 2 likewise represent the electrode sections interconnected mechanically and electrically by the nipple joints 3. The whole weight of the electrode is carried by a special supporting device not illustrated.

From a yoke carried by the main lifting and supporting means there is suspended via several intermediate and unimportant elements the supporting ring 48 concentrieally encompassing the electrode 1 at a distance.

Pendants 9 which are adjustable lengthwise by turnbuckles 8 are pivotally connected with solid journal bearings 7 fixed to supporting ring 48, for example by casting. The current supply plates 11 are flexibly connected by means of their upper solid journal bearings with pendants 9 and by means of their lower solid journal bearings 12 with pendants 13 which are adjustable lengthwise by turnbuckles 14. Pendants 13, on their part, are flexibly linked by way of their lower eyes with the solid journal bearings 15 of the lower system of current supply plates 16.

The upper pressure ring consists of interconnected pressure cylinders 49 which encircle the electrode in the form of a ring, the number of pressure cylinders corresponding to the number of current supply plates.

The lower pressure ring is composed in analogous manner of a number of pressure cylinders 50.

The upper and the lower pressure rings are rigidly suspended by supporting tubes 51 and 52 from supporting ring 48.

The supporting tubes 51 and 52 simultaneously serve to supply and to remove the cooling water necessary for cooling the double-walled cylinder jackets and the doublewalled cylinder covers facing the electrode. Pressure cylinders '49 and Sil are closed outwardly by cylinder covers.

Pressure pistons 53 disposed in pressure cylinders 49 are provided with piston rods 59 which project through the inner cylinder covers and are linked with small bearing blocks 57 firmly connected with the current supply plates. Between the inner sides of pistons 53 and the cylinder covers facing the electrode the pressure springs 54 are installed.

When a pressure medium, preferably compressed air, is introduced into the cylinders 49 through short pipes 61, the pressure pistons compress pressure springs 54 in the direction of the electrode axis and force the upper system of current supply plates 11 into contact with the electrode 1. When the pressure subsides the pressure springs 54 relax pushing the pressure pistons again out wards whereby the current supply plates 11 are withdrawn from the electrode 1 or kept in said position.

The lower system of current supply plates 16 is operated in analogous manner by means of pressure cylinders 50, pressure pistons 56, piston rods 60 linked with small bearing blocks 58. In this case the pressure springs are disposed, however, on the side of the pressure piston turned away from the electrode and the short pipes for the pressure medium are arranged near the cylinder cover facing the electrode. In this arrangement the current supply plates 16 are pressed on the electrode section 2 by the force of pressure springs 55 when no pressure medium is allowed to flow in, while they are withdrawn from the electrode section 2 against the force of pressure springs 55 as soon as the pressure medium is introduced into the cylinders through short pipes 62.

The lower system of current supply plates 16 inclusive of the pressure cylinders 50 is surrounded with protective shell 63 provided with short pipe 64 for the supply and removal of cooling water. The current supply plates 11 and 16 and pressure rings 49 and 56 are similarly cooled by means of water.

In view of the functional independence of the individual driving elements of one another, the devices shown in Figures 1 and 2 permit an individual tightening of the current supply plates also on pre-baked and unmachined electrodes in spite of the possible deviations from the actual values of the diameter, the cross-sectional shape and the eccentricity.

As compared with devices having only one system of current supply plates, the arrangement of two mechanically independent but electrically connected systems of current supply plates reduces the difliculty arising from the current passage through the conical or cylindrical nipple connection at the joint area of two electrode sections due to the inferior electrical conductivity prevailing in said area.

In normal operation, the current is conducted to the electrode by way of the lower system of current supply plates while the upper system of current supply plates is held at a sufficient distance from the electrode. When, on lowering the electrode, an electrode joint has passed the upper system of current supply plates, said upper system is pressed on the electrode while the current supply plates of the lower system are withdrawn from the electrode. Since both systems are electrically interconnected it. is not necessary to break the current.

The nipple connection principally carries current only as long as the upper system of current supply plates is pressed on the electrode.

Due to the fact that a machining of pie-baked elecrodes can be dispensed with the devices according to the invention considerably reduce the price of the electrodes. if desired the devices according to the invention are likewise suitable for pie-baked, machined and selfbaking electrodes.

We claim:

1. Apparatus for tightening and loosening current supply plates on electrodes in electric furnaces comprising two vertically disposed, separate, independently controlable and independently operated systems of current supply plates, said plate systems being electrically interconnected, means for supporting the two independent sysems whereby the distance between the systems is always the same, said means comprising suspension means pivotally connected with the upper portion of the lower system of current supply plates and the lower end of the upper system of current supply plates and suspension means pivotally connected with the upper portion of said upper plate system and a main support positioned on the electrode and lying above the upper plate system, control means connected with each plate system for tightening and loosening said current supply plate systems with respect to the electrode, and pressure applying means connected with said control means of each plate system to operate said control means.

2. Apparatus as claimed in claim 1 comprising two individually controllable and independently operated control means for independently tightening both systems of current supply plates, and separate, independently oper ated pressure applying means connected with each control means.

3. Apparatus as claimed in claim 2 comprising pressure applying means which self-tighten the lower system of current supply plates and which release the plate system through a counter pressure, and pressure applying means which tighten the upper system of current supply plates through application of pressure and which is self-releasing when the pressure is relieved to loosen the plates.

4. Apparatus as claimed in claim 1 comprising control means which extend axially of the electrode.

5. Apparatus as claimed in claim 1 comprising control means which extend radially of the electrode.

6. Apparatus as claimed in claim 1 wherein the electrode is a. prebaked, unmachined electrode of uneven diameter.

References Cited in the file of this patent UNITED STATES PATENTS 1,677,712 Dion July 17, 1928 1,728,070 Miguet Sept. 10, 1929 1,836,880 Sem Dec. 15, 1931 2,363,078 Nissim Nov. 21, 1944 2,668,183 Foyn Feb. 2, 1954 2,778,865 Kongsgaarden Jan. 22, 1957 2,812,375 Newhall et al. Nov. 5, 1957 2,845,468 Haavik July 29, 1958 2,872,494 Rumberg et al. Feb. 3, 1959 2,903,494 Meffert Sept. 8, 1959 OTHER REFERENCES Germany, D 12315 VIII d/2lh, Aug. 9, 1956. 

